/*
 * FreeModbus Libary: A portable Modbus implementation for Modbus ASCII/RTU.
 * Copyright (c) 2006 Christian Walter <wolti@sil.at>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. The name of the author may not be used to endorse or promote products
 *    derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 * File: $Id: mbfuncholding.c,v 1.12 2007/02/18 23:48:22 wolti Exp $
 */

/* ----------------------- System includes ----------------------------------*/
#include "stdlib.h"
#include "string.h"

/* ----------------------- Platform includes --------------------------------*/
#include "port.h"

/* ----------------------- Modbus includes ----------------------------------*/
#include "mb.h"
#include "mbframe.h"
#include "mbproto.h"
#include "mbconfig.h"

/* ----------------------- Defines ------------------------------------------*/
#define MB_PDU_FUNC_READ_ADDR_OFF               ( MB_PDU_DATA_OFF + 0)
#define MB_PDU_FUNC_READ_REGCNT_OFF             ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_READ_SIZE                   ( 4 )
#define MB_PDU_FUNC_READ_REGCNT_MAX             ( 0x007D )

#define MB_PDU_FUNC_WRITE_ADDR_OFF              ( MB_PDU_DATA_OFF + 0)
#define MB_PDU_FUNC_WRITE_VALUE_OFF             ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_WRITE_SIZE                  ( 4 )

#define MB_PDU_FUNC_WRITE_MUL_ADDR_OFF          ( MB_PDU_DATA_OFF + 0 )
#define MB_PDU_FUNC_WRITE_MUL_REGCNT_OFF        ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF       ( MB_PDU_DATA_OFF + 4 )
#define MB_PDU_FUNC_WRITE_MUL_VALUES_OFF        ( MB_PDU_DATA_OFF + 5 )
#define MB_PDU_FUNC_WRITE_MUL_SIZE_MIN          ( 5 )
#define MB_PDU_FUNC_WRITE_MUL_REGCNT_MAX        ( 0x0078 )

#define MB_PDU_FUNC_READWRITE_READ_ADDR_OFF     ( MB_PDU_DATA_OFF + 0 )
#define MB_PDU_FUNC_READWRITE_READ_REGCNT_OFF   ( MB_PDU_DATA_OFF + 2 )
#define MB_PDU_FUNC_READWRITE_WRITE_ADDR_OFF    ( MB_PDU_DATA_OFF + 4 )
#define MB_PDU_FUNC_READWRITE_WRITE_REGCNT_OFF  ( MB_PDU_DATA_OFF + 6 )
#define MB_PDU_FUNC_READWRITE_BYTECNT_OFF       ( MB_PDU_DATA_OFF + 8 )
#define MB_PDU_FUNC_READWRITE_WRITE_VALUES_OFF  ( MB_PDU_DATA_OFF + 9 )
#define MB_PDU_FUNC_READWRITE_SIZE_MIN          ( 9 )

/* ----------------------- Static functions ---------------------------------*/
eMBException    prveMBError2Exception(eMBErrorCode eErrorCode);

/* ----------------------- Start implementation -----------------------------*/

#if MB_FUNC_WRITE_HOLDING_ENABLED > 0

eMBException
eMBFuncWriteHoldingRegister(UCHAR* pucFrame, USHORT* usLen)
{
	USHORT          usRegAddress;
	eMBException    eStatus = MB_EX_NONE;
	eMBErrorCode    eRegStatus;

	if(*usLen == (MB_PDU_FUNC_WRITE_SIZE + MB_PDU_SIZE_MIN)) {
		usRegAddress = (USHORT)(pucFrame[MB_PDU_FUNC_WRITE_ADDR_OFF] << 8);
		usRegAddress |= (USHORT)(pucFrame[MB_PDU_FUNC_WRITE_ADDR_OFF + 1]);
		usRegAddress++;

		/* Make callback to update the value. */
		eRegStatus = eMBRegHoldingCB(&pucFrame[MB_PDU_FUNC_WRITE_VALUE_OFF],
		                             usRegAddress, 1, MB_REG_WRITE);

		/* If an error occured convert it into a Modbus exception. */
		if(eRegStatus != MB_ENOERR) {
			eStatus = prveMBError2Exception(eRegStatus);
		}
	} else {
		/* Can't be a valid request because the length is incorrect. */
		eStatus = MB_EX_ILLEGAL_DATA_VALUE;
	}

	return eStatus;
}
#endif

#if MB_FUNC_WRITE_MULTIPLE_HOLDING_ENABLED > 0
eMBException
eMBFuncWriteMultipleHoldingRegister(UCHAR* pucFrame, USHORT* usLen)
{
	USHORT          usRegAddress;
	USHORT          usRegCount;
	UCHAR           ucRegByteCount;

	eMBException    eStatus = MB_EX_NONE;
	eMBErrorCode    eRegStatus;

	if(*usLen >= (MB_PDU_FUNC_WRITE_MUL_SIZE_MIN + MB_PDU_SIZE_MIN)) {
		usRegAddress = (USHORT)(pucFrame[MB_PDU_FUNC_WRITE_MUL_ADDR_OFF] << 8);
		usRegAddress |= (USHORT)(pucFrame[MB_PDU_FUNC_WRITE_MUL_ADDR_OFF + 1]);
		usRegAddress++;

		usRegCount = (USHORT)(pucFrame[MB_PDU_FUNC_WRITE_MUL_REGCNT_OFF] << 8);
		usRegCount |= (USHORT)(pucFrame[MB_PDU_FUNC_WRITE_MUL_REGCNT_OFF + 1]);

		ucRegByteCount = pucFrame[MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF];

		if((usRegCount >= 1) &&
		        (usRegCount <= MB_PDU_FUNC_WRITE_MUL_REGCNT_MAX) &&
		        (ucRegByteCount == (UCHAR)(2 * usRegCount))) {
			/* Make callback to update the register values. */
			eRegStatus =
			    eMBRegHoldingCB(&pucFrame[MB_PDU_FUNC_WRITE_MUL_VALUES_OFF],
			                    usRegAddress, usRegCount, MB_REG_WRITE);

			/* If an error occured convert it into a Modbus exception. */
			if(eRegStatus != MB_ENOERR) {
				eStatus = prveMBError2Exception(eRegStatus);
			} else {
				/* The response contains the function code, the starting
				 * address and the quantity of registers. We reuse the
				 * old values in the buffer because they are still valid.
				 */
				*usLen = MB_PDU_FUNC_WRITE_MUL_BYTECNT_OFF;
			}
		} else {
			eStatus = MB_EX_ILLEGAL_DATA_VALUE;
		}
	} else {
		/* Can't be a valid request because the length is incorrect. */
		eStatus = MB_EX_ILLEGAL_DATA_VALUE;
	}

	return eStatus;
}
#endif

#if MB_FUNC_READ_HOLDING_ENABLED > 0

eMBException
eMBFuncReadHoldingRegister(UCHAR* pucFrame, USHORT* usLen)
{
	USHORT          usRegAddress;
	USHORT          usRegCount;
	UCHAR*          pucFrameCur;

	eMBException    eStatus = MB_EX_NONE;
	eMBErrorCode    eRegStatus;

	if(*usLen == (MB_PDU_FUNC_READ_SIZE + MB_PDU_SIZE_MIN)) {
		usRegAddress = (USHORT)(pucFrame[MB_PDU_FUNC_READ_ADDR_OFF] << 8);
		usRegAddress |= (USHORT)(pucFrame[MB_PDU_FUNC_READ_ADDR_OFF + 1]);
		usRegAddress++;

		usRegCount = (USHORT)(pucFrame[MB_PDU_FUNC_READ_REGCNT_OFF] << 8);
		usRegCount |= (USHORT)(pucFrame[MB_PDU_FUNC_READ_REGCNT_OFF + 1]);

		/* Check if the number of registers to read is valid. If not
		 * return Modbus illegal data value exception.
		 */
		if((usRegCount >= 1) && (usRegCount <= MB_PDU_FUNC_READ_REGCNT_MAX)) {
			/* Set the current PDU data pointer to the beginning. */
			pucFrameCur = &pucFrame[MB_PDU_FUNC_OFF];
			*usLen = MB_PDU_FUNC_OFF;

			/* First byte contains the function code. */
			*pucFrameCur++ = MB_FUNC_READ_HOLDING_REGISTER;
			*usLen += 1;

			/* Second byte in the response contain the number of bytes. */
			*pucFrameCur++ = (UCHAR)(usRegCount * 2);
			*usLen += 1;

			/* Make callback to fill the buffer. */
			eRegStatus = eMBRegHoldingCB(pucFrameCur, usRegAddress, usRegCount, MB_REG_READ);

			/* If an error occured convert it into a Modbus exception. */
			if(eRegStatus != MB_ENOERR) {
				eStatus = prveMBError2Exception(eRegStatus);
			} else {
				*usLen += usRegCount * 2;
			}
		} else {
			eStatus = MB_EX_ILLEGAL_DATA_VALUE;
		}
	} else {
		/* Can't be a valid request because the length is incorrect. */
		eStatus = MB_EX_ILLEGAL_DATA_VALUE;
	}

	return eStatus;
}

#endif

#if MB_FUNC_READWRITE_HOLDING_ENABLED > 0

eMBException
eMBFuncReadWriteMultipleHoldingRegister(UCHAR* pucFrame, USHORT* usLen)
{
	USHORT          usRegReadAddress;
	USHORT          usRegReadCount;
	USHORT          usRegWriteAddress;
	USHORT          usRegWriteCount;
	UCHAR           ucRegWriteByteCount;
	UCHAR*          pucFrameCur;

	eMBException    eStatus = MB_EX_NONE;
	eMBErrorCode    eRegStatus;

	if(*usLen >= (MB_PDU_FUNC_READWRITE_SIZE_MIN + MB_PDU_SIZE_MIN)) {
		usRegReadAddress = (USHORT)(pucFrame[MB_PDU_FUNC_READWRITE_READ_ADDR_OFF] << 8U);
		usRegReadAddress |= (USHORT)(pucFrame[MB_PDU_FUNC_READWRITE_READ_ADDR_OFF + 1]);
		usRegReadAddress++;

		usRegReadCount = (USHORT)(pucFrame[MB_PDU_FUNC_READWRITE_READ_REGCNT_OFF] << 8U);
		usRegReadCount |= (USHORT)(pucFrame[MB_PDU_FUNC_READWRITE_READ_REGCNT_OFF + 1]);

		usRegWriteAddress = (USHORT)(pucFrame[MB_PDU_FUNC_READWRITE_WRITE_ADDR_OFF] << 8U);
		usRegWriteAddress |= (USHORT)(pucFrame[MB_PDU_FUNC_READWRITE_WRITE_ADDR_OFF + 1]);
		usRegWriteAddress++;

		usRegWriteCount = (USHORT)(pucFrame[MB_PDU_FUNC_READWRITE_WRITE_REGCNT_OFF] << 8U);
		usRegWriteCount |= (USHORT)(pucFrame[MB_PDU_FUNC_READWRITE_WRITE_REGCNT_OFF + 1]);

		ucRegWriteByteCount = pucFrame[MB_PDU_FUNC_READWRITE_BYTECNT_OFF];

		if((usRegReadCount >= 1) && (usRegReadCount <= 0x7D) &&
		        (usRegWriteCount >= 1) && (usRegWriteCount <= 0x79) &&
		        ((2 * usRegWriteCount) == ucRegWriteByteCount)) {
			/* Make callback to update the register values. */
			eRegStatus = eMBRegHoldingCB(&pucFrame[MB_PDU_FUNC_READWRITE_WRITE_VALUES_OFF],
			                             usRegWriteAddress, usRegWriteCount, MB_REG_WRITE);

			if(eRegStatus == MB_ENOERR) {
				/* Set the current PDU data pointer to the beginning. */
				pucFrameCur = &pucFrame[MB_PDU_FUNC_OFF];
				*usLen = MB_PDU_FUNC_OFF;

				/* First byte contains the function code. */
				*pucFrameCur++ = MB_FUNC_READWRITE_MULTIPLE_REGISTERS;
				*usLen += 1;

				/* Second byte in the response contain the number of bytes. */
				*pucFrameCur++ = (UCHAR)(usRegReadCount * 2);
				*usLen += 1;

				/* Make the read callback. */
				eRegStatus =
				    eMBRegHoldingCB(pucFrameCur, usRegReadAddress, usRegReadCount, MB_REG_READ);

				if(eRegStatus == MB_ENOERR) {
					*usLen += 2 * usRegReadCount;
				}
			}

			if(eRegStatus != MB_ENOERR) {
				eStatus = prveMBError2Exception(eRegStatus);
			}
		} else {
			eStatus = MB_EX_ILLEGAL_DATA_VALUE;
		}
	}

	return eStatus;
}

#endif
